Mark Zuckerberg wrote in a Facebook note that he is "committed" to building a social network where people can speak freely without fear of violence. In 2010, a Pakistani lawyer attempted to have Mr. Zuckerberg put to death over drawings of Muhammad that appeared on the site.

On Friday morning, the Facebook founder posted a note on the site decrying the terror attack against the magazine earlier this week and pledging that Facebook will always be a place where users’ freedom of speech is protected.

“I’m committed to building a service where you can speak freely without fear of violence,” Mr. Zuckerberg wrote.

Zuckerberg has some experience with the threat of extremist violence in response to free speech. In 2010, Pakistani lawyer Muhammad Azhar Siddique attempted to have Zuckerberg and other Facebook co-founders put to death for refusing to take down drawings of the prophet Muhammad that Facebook users posted to the site. (The Deputy Attorney General of Pakistan launched a criminal investigation into the matter, but no Facebook employees or users were arrested or harmed.)

“As I reflect on [the attack on Charlie Hebdo] and my own experience with extremism,” Zuckerberg wrote in his note, “this is what we all need to reject -- a group of extremists trying to silence the voices and opinions of everyone else around the world. I won’t let that happen on Facebook.”

Facebook has repeatedly refused to remove content that religious groups find offensive, as in 2010 when a German user began a worldwide “Draw Muhammad” contest on the site. However, Facebook does respond to government requests to remove material considered blasphemous. Last year, the company removed 4960 pieces of content in India, 1893 pieces of content in Turkey, and 1773 pieces of content in Pakistan; Facebook said its third annual transparency report that most of this content was removed in response to local laws prohibiting criticism of religion or of the state.

Facebook was briefly banned in Pakistan in 2010, after it declined to remove drawings of Muhammad, but was reintroduced after the company agreed to block the content for Pakistani users. It’s currently blocked in Iran and China. Many Muslim communities consider it blasphemous to draw Muhammad for any reason.

A Pew report released on Friday showed that 71 percent of online adults worldwide use Facebook, and that 70 percent of users check in at least once a day -- so protecting free speech on the world’s dominant social media platform is a big deal. Many analysts have argued that teenagers and 20-somethings are fleeing Facebook for hipper platforms, but the Pew report show that more than half of Internet users between 18 and 29 are on Instagram, which is owned by Facebook.